Tool drive assembly with integrated magnetic displacement monitoring system

Abstract

A drive assembly for portable, hand-held, battery powered tools is provided. The drive assembly includes a motor, a gear assembly, a lead drive shaft, a jaw drive member and a magnetic displacement monitoring system. The gear assembly is coupled to the motor and the lead drive shaft is operatively coupled to the gear assembly. The magnetic displacement monitoring system has at least one magnet coupled to the lead drive shaft, at least one magnetic field sensor disposed adjacent to the magnet, and a processing element electrically coupled to the magnetic field sensor. As the motor runs, the lead drive shaft rotates about an axis and the jaw drive member moves along the lead drive shaft. The magnetic field sensor senses the change in magnetic field and sends at least one signal to the processing element which determines the location of the jaw drive member along the lead drive shaft.

What is claimed is: 
     
         1 . A drive assembly for a portable, hand-held tool, the drive assembly comprising:
 a motor;   a gear assembly coupled to the motor;   a lead drive shaft having a distal end portion and a proximal end portion;   a jaw drive member movable along the lead drive shaft as the lead drive shaft rotates about an axis; and   a magnetic displacement monitoring system comprising at least one magnet having a magnetic field, the at least one magnet coupled to the lead drive shaft, at least one magnetic field sensor disposed adjacent to the magnet wherein the magnetic field sensor is configured to sense the magnetic field as the lead drive shaft rotates about the axis, and a processing element electrically coupled to the magnetic field sensor configured to receive at least one signal from the magnetic field sensor and determine a position of the jaw drive member as it moves along the lead drive shaft.   
     
     
         2 . The drive assembly according to  claim 1 , wherein the at least one magnet is diametrically polarized. 
     
     
         3 . The drive assembly according to  claim 1 , wherein the at least one magnet is one of a radial magnet, cylindrical magnet, or ring magnet. 
     
     
         4 . The drive assembly according to  claim 1 , wherein the at least one magnet is a dipole magnet. 
     
     
         5 . The drive assembly according to  claim 1 , wherein the at least one magnet is a quadrupole magnet. 
     
     
         6 . The drive assembly according to  claim 1 , wherein the processing element slows the motor when the drive member reaches a predefined point along the lead drive shaft. 
     
     
         7 . The drive assembly according to  claim 1 , wherein the processing element stops power being supplied to the motor when the drive member reaches a predefined point on the lead drive shaft. 
     
     
         8 . The drive assembly according to  claim 1 , wherein the motor automatically reverses after the drive member reaches a predefined point on the lead drive shaft. 
     
     
         9 . A drive assembly for a portable, hand-held tool, the drive assembly comprising:
 a drive assembly housing;   a motor housed within the drive assembly housing;   a gear assembly housed within the drive assembly housing;   a lead drive shaft having a distal end portion and a proximal end portion, the distal end portion being threaded and substantially outside the drive assembly housing;   a drive member movable along the lead drive shaft as the lead drive shaft rotates about an axis;   a magnetic displacement monitoring system having at least one magnet coupled to the distal end portion of the lead drive shaft, at least one magnetic field sensor disposed substantially adjacent to the magnet such that the magnetic field sensor detects a change to the magnetic field as the magnet rotates about the axis in relation to the lead drive shaft, and a processing element operatively coupled to the magnetic field sensor, wherein the processing element calculates the position of the drive member along the lead drive shaft; and   a bearing system positioned at least partially within the drive assembly housing.   
     
     
         10 . The drive assembly according to  claim 9 , wherein the at least one magnet is diametrically polarized. 
     
     
         11 . The drive assembly according to  claim 9 , wherein the at least one magnet is one of a radial magnet, cylindrical magnet, or ring magnet. 
     
     
         12 . The drive assembly according to  claim 9 , wherein the at least one magnet is a dipole magnet. 
     
     
         13 . The drive assembly according to  claim 9 , wherein the at least one magnet is a quadrupole magnet. 
     
     
         14 . The drive assembly according to  claim 9 , wherein the processing element slows the motor when the drive member reaches a predefined point along the lead drive shaft. 
     
     
         15 . The drive assembly according to  claim 9 , wherein the processing element stops power being supplied to the motor when the drive member reaches a predefined point on the lead drive shaft. 
     
     
         16 . A magnetic displacement monitoring system comprising:
 at least one magnet having a magnetic field and operatively associated with a lead drive shaft;   at least one magnetic field sensor disposed adjacent to the magnet wherein the magnetic field sensor is configured to sense the magnetic field as the magnet is rotated about an axis; and   a processing element electrically coupled to the magnetic field sensor and configured to monitor rotation of the lead drive shaft based on the sensed magnetic field.   
     
     
         17 . The magnetic displacement monitoring system according to  claim 16 , wherein the at least one magnet is diametrically polarized. 
     
     
         18 . The magnetic displacement monitoring system according to  claim 16 , wherein the at least one magnet is a radial magnet, cylindrical magnet, or ring magnet. 
     
     
         19 . The magnetic displacement monitoring system according to  claim 16 , wherein the at least one magnet is a dipole magnet. 
     
     
         20 . The magnetic displacement monitoring system according to  claim 16 , wherein the at least one magnet is a quadrupole magnet. 
     
     
         21 . The magnetic displacement monitoring system according to  claim 16 , wherein the processing element slows the motor when the drive member reaches a predefined point along the lead drive shaft. 
     
     
         22 . The magnetic displacement monitoring system according to  claim 16 , wherein the processing element stops power being supplied to the motor when the drive member reaches a predefined point on the lead drive shaft.